As is known there exist several circumstances, of traumatic and/or pathological nature, which involve the application of a prosthesis of the ankle.
This prosthesis is set between the terminal part of the tibia and the upper part of the talus, to replace the original articulation in all respects.
The ankle prostheses typically comprise a tibial component, which is fixed to the terminal part of the tibia, and a talar component, which is fixed to the upper part of the talus. Between the tibial component and the talar component a third component is interposed, suitably shaped so as to enable the first two components to move reciprocally and hence provide, from the mechanical viewpoint, functionalities similar to those typically provided by a natural articulation.
Applicants have noted that the prostheses available nowadays imply surgical operations of application which are considerably complicated, both in terms of access to the area at which the operation is required, and in terms of machining/shaping of the bones to which the components of the prosthesis have to be secured.
For example, some prostheses require a lateral-type operation, which involves removal of some intact and functional bone portions (e.g. fibula), which otherwise would not be affected by the surgical operation.
These prostheses also require forming a pair of grooves (imagining the patient in a standing position, these grooves are arranged horizontally and transversely to the direction in which the patient would walk) in the terminal part of the tibia. Also this machining operation, besides being complex from the viewpoint of its execution, causes a very in-depth machining of a portion of a substantially healthy bone.
From the viewpoint of the talar component, it often requires a multiplicity of steps of cutting/shaping of the talus, which renders the surgical operation further complex and risky.
In fact, the drawbacks mentioned above, besides impacting on the difficulty of the operation in general, also involve risks both for the patient (in case of a defective result of the intervention) and for the surgeon who performs the surgical intervention, from the viewpoint of his/her professional responsibility.
It should also be noted that, often, surgeons are not able to deal with an operation of this nature (which, moreover, requires a long learning curve), such that they fall back to the alternative consisting of the arthrodesis, i.e., the “joining” or “fusion” of the articulation. This leads to the permanent loss of the articular functionality and the ensuing condition of permanent disability. It is clear that this type of solution penalizes in an unacceptable way the patient, to whom a treatment of a completely different nature should be offered.